Internal combustion engine



May 17, 1938. E. G. REID I 2,117,983

I INTERNAL COMBUSTION ENGINE Filed Nov. 29, 1935 III, I, II'III/ I Z5 5/L23 3/ 49 ,,IIIIIIIIIIII j llllll llll Patented May 17, 1938 UNITEDSTATES PATENT OFFICE 13 Claims.

The present invention relates to internal combustion engines andparticularly to intake manifolds for engines of this class.

As is well-known, the present tendency of builders of internalcombustion engines is to design and construct such engines withrelatively numerous cylinders with the end in view of realizing theadvantage of greater uniformity of power delivery for a given combinedcylinder volume, and to obtain other recognized advantages. Especiallywhere such an engine is to be employed as a means for supplying powerfor propelling an automotive vehicle is it appreciated that an enginehaving a considerable number of cylinders has advantages over thoseemploying relatively few cylinders. Numerous automobile engines now inuse have eight cylinders, and some have more. It is also desirable tomake use of only ane carburetor or fuel and air mixing device and toprovide what is designated an inlet or intake manifold by means of whichsuch single carburetor is connected to all of thegcylinders of theengines for the purpose of supplying each cylinder with the requisiteamount of fuel. Naturally, the several pistons being connected to acommon crank shaft, the power developed in each cylinder by the ignitionof any explosive charge introduced should be equal in magnitude to thepower developed in each of the other cylinders in subsequent explosionsas otherwise nonuniformity of operation of the engine would result.

The problem of supplying all cylinders of a multi-cylinder internalcombustion engine with equal charges of fuel from a common carburetorhas, however, not been an easy one to exactly solve and, while manyattempts to bring about this desirable result have heretofore been made,no entirely satisfactory, solution has been 40 reached. Thus it is foundthat, notwithstanding all precautions which it has heretofore beenconsidered possible to take, certain of the cylinders of an engine arefrequently supplied with charges which do not have the same power valuesupon explosion or ignition as have the charges supplied to othercylinders. It will be appreciated that each cylinder is onlyintermittently charged and that the piston therein is onlyintermittently driven upon its working stroke by expansion of theignited charge. In other words, by reason of the action of the inletvalve of such cylinder, the flow of combustible mixture thereto isintermittently initiated and halted. This intermittent starting andstopping of the flow of combustible charge results in what aredesignated manifold pressure waves, surges, or oscillations, whichtravel backwardly from the inlet valves toward the carburetor and whichtend to destroy the uniformity of the fuel and air mixing action of thecarburetor by varying the velocity of the air flowing through thecarburetor throat. It has previously been suggested that thesevariations of Velocity at the carburetor throat may be minimized by theinsertion, intermediate the carburetor and the conduits which lead tothe engine cylinders, 'of means for damping the oscillations mentionedand thus preventing such oscillations from modifying the action of thecarburetor.

The present invention contemplates the provision of an improved means ofthis character the primary purpose of which is to totally eliminate, orat least to so reduce as to render unimportant, the surges or pressurewaves previously referred to and which have heretofore so greatly 0disturbed carburetion. This I accomplish by designing the intakemanifold so that it has intermediate the carburetor and the several conduits which lead to the cylinders of the engine,

a chamber in which'a substantial body of the 25 fuel and gas mixture istemporarily confined on its way to the engine, this chamber being sodesigned and constructed that the temporarily confined body of gas iscaused to circulate rapidly along or around a closed or endless path.This U arrangement interposes between the carburetor and the enginecylinders what may be called a gaseous fly-wheel which, like itsmechanical analogue, continues to rotate at a substantially constantangular velocity despite the application of fluctuating accelerating andretarding impulses. Thus the pressure waves originating at the valvesare transformed into unimportantly small variations of the velocity ofthe gaseous fly-wheel and a practically steady, unidirectional flowthrough the carburetor is maintained. The net result is increasedefficiency of operation of the carburetor and more equal distribution ofthe combustible charges to the several cylinders.

Likewise the Volumetric efficiency of an internal combustion engine withwhich the improved manifold is used is considerably increased. Thecharges flowing to the several cylinders are withdrawn tangentially fromthe whirling or rotating body of the fuel and air mixture instead ofbeing drawn from a body of such mixture which may be stagnant, or evensurging away from the cylinder, at that instant. Superior velocities offlow into the several cylinders, respectively, of the gaseous fuelmixture are therefore realized.

The specific means for accomplishing the objects of the invention may bevaried somewhat in accordance with the fuel used, the number ofcylinders of the engine and other factors, but in each instance achamber will be provided intermediate the carburetor cr gas and airmixing device and the cylinders within which may be temporarily trappeda body of the fuel and air mixciably less than the volume of any singlecylinder to which it is connected. It is best tointroduce the mixturethrough spiral passages which open into the toroidal chamber throughports in its inner wall and the discharge ends of the passages should beuniformly inclined in the same direction so as to deliver streams ofmixture as nearly tangentially into the chamber as is possible; thusunidirectional motion of the entrapped gas is created with the minimumloss of energy. Gas is withdrawn from the toroidal chamber through twoor more apertures formed in the outer wall of the chamberat equallyspaced intervals and immediately passes into tangentially arrangedconduits. These conduits communicate with branch ducts or conduitsconnected to the several cylinders.

An embodiment of the invention selected for disclosure by way of exampleis illustrated in the accompanying drawing, in which Figure 1 is arather diagrammatic view showing in plan a multi-cylinder internalcombustion engine to which the invention has been applied;

Figure 2 is a section on line 22 of Figure 1;

Figure 3 is a section on line 3-3 of Figure 2; Figure 4 is a section online 4-4 of Figure 1;

and

Figure 5 is a partial section on the line 5-5 of Figure l.

The cylinder block of the engine diagrammatically shown in Figure l isillustrated at IE3. No details of the engine proper are shown but itwill be understood that the engine may be of any type or design whichincludes inlet valves controlling the fiow of the fuel and air mixturethrough suitable passages into the several cylinders, respectively. Theengine illustrated is pro vided with eight cylinders and. the axes ofthese cylinders are disposed in a common plane. It will be understood,however, that the invention is applicable to engines with all othercylinder arrangements as well as to engines of the in line type. In thiscase, the cylinders are arranged in groups of two for fuel feedingpurposes, the outermost groups being supplied with combustible chargesthrough conduits H and i2 and the innermost groups through conduits l3and M. The inlet ends of conduits l! and i2 communicate re" spectivelywith a chamber and the inlet ends of conduits I3 and I4 are incommunication with a second chamber I8, closely adjacent chamber I5 butnot communicating therewith. The toroidal gas chamber is indicatedgenerally at El and the outer wall of this chamber is provided withapertures to permit the outflow of mixture into tangentially arrangedducts or conduits l8 and I9, respectively. Tangential duct l8communicates with the downwardly and inwardly turned manifold pipe andduct 59 communicates with the downwardly and inwardly turned manifoldpipe 25, the outlet ends of these pipes communicating with chambers l5and [6, respectively, previously described.

A portion of a carburetor is indicated at 25, this carburetor beingpositioned above and coaxially with the toroidal chamber I? and being ofthe down-draft type. It will be understood, however, that the inventionmay be used with full success with carburetors other than those of thedown-draft type. The outlet port 26 of the carburetor is in registerwith a central similarly shaped aperture formed in a flange-like element2'! and the gaseous mixture flowing downwardly through the carburetorport 2i? is transmitted to the toroidal chamber through a passage whichbrings this port into communication with all parts of the chamber, 1.e., the passage is brought into communication with a continuous apertureor slot 28 formed in what maybe designated the inner wall of chamberl'i.

The passage just briefly referred to is defined by the generally conicallower wall 29 and the frusto conical upper wall 30, these walls beingpreferably formed integrally with the walls 5'! of the toroidal chambersince the entire unit, including the ducts ifl, if), 29 and 2i mayconveniently comprise a single casting, thus simplifying constructionand installation. As shown in Figures 2 and 4, the walls 29 and 3Gconverge as they approach the circular port 23 so that the passage isconstantly reduced in vertical section as it expands circumferentially.The convergence of the walls 29 and is such as to maintain thecross-sectional area of the passage leading to the chamber ill at anapproximately constant value at all radii; the specific form of thepassage will depend upon the actual dimensions and velocities involvedin its design but the objective of such convergence shall be thereduction of re sistance arising from skin friction and discontinuousflow.

In order that the downfiowing fuel and air mixture moving toward thetoroidal chamber shall be directed so as to cause the body of mixturewithin that chamber to be in a state of rapid rotation about the axis ofthe toroid, a plurality of curved vanes 3! are provided which vanes, in

, effect, divide the downfiowing stream of fuel mixture into a pluralityof individual streams, all of which are discharged into the toroidalchamber in substantially tangential directions.

The carburetor employed may be of any desired type provided itefliciently mixes the liquid fuel with the air passing therethrough andit may be supported entirely by the unit including the toroidal chamber.In fact, the chamber 11 and its associated inlet and outlet passages maybe formed as a unit suitable for ready application to existing types ofinternal combustion engines, this unit being merely inserted between thecarburetor device and the several conduits which lead to the enginecylinders. V

The fiow of the fuel and air mixture through the several passages justdescribed is of course brought about by operation of the engine, suchoperation causing the necessary suction. The fuel and air mixturedelivered by the carburetor passes at high velocity into the toroidalchamber ll, the vanes 3| dividing the gaseous stream into smallerstreams and directing these smaller streams into this chamber in suchmanner that the body of mixture therein is causedto circulate rapidlyabout the axis of the toroid. The mix- 'ture makes its escape from thechamber through tor is therefore not influenced by valve closures andthe carburetion of the liquid fuel proceeds uniformly at all times. Thewithdrawal of the fuel mixture tangentially from the toroidal chamber,and at higher than customary velocity, facilitates introduction of thefuel mixture into the several cylinders and generally increases thevolumetric efiiciency of the engine. In order that the maximumeificiency of the invention may be realized, care should be taken thatno single conduit leading from the toroidal chamber to the engine shouldcommunicate with cylinders the inlet valves of which are simultaneouslyopen.

While I prefer that the toroidal chamber shall be circular incross-section, because this minimizes loss in velocity due to frictionbetween the fuel mixture and the walls of the chamber, the exactcross-sectional shape of the chamber may be varied if desired for otherreasons and the design and arrangement of the component elements of theinvention may be otherwise modified so long as a body of continuouslycirculating fuel and air mixture is maintained intermediate thecarburetor and engine to accomplish the specified functions.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. The combination with a multi-cylinder internal combustion engine ofan inlet manifold comprising a toroidal chamber adapted to receive amixture of fuel and air and to guide the same along a closedunrestricted path, means for delivering a fuel-air mixture into saidchamber in a direction to cause movement of the mixture along said path,and conduits for leading streams of said mixture from said chamber tothe engine cylinders.

2. The combination with a multi-cylinder internal combustion engine ofan inlet manifold comprising an elongated chamber of substantiallyconstant cross-section for guiding a fuelair mixture along a closedunrestricted path, the volume of said chamber being not substantiallyless than the Volume of one cylinder of the engine, means for deliveringa fuel-air mixture into said chamber in a direction to cause movement ofsuch mixture along said path, and conduits for leading streams of saidmixture from said chamber to the engine cylinders.

3. The combination with a multi-cylinder internal combustion engine ofan inlet manifold comprising an elongated chamber of substantiallyconstant cross-section for guiding a fuel-air mixture along an endlesspath, stationary gas guiding means for directing into said chamber indirections substantially tangential to the chamber, a plurality ofstreams of fuel-air mixture to create a revolving body of such mixture,and conduits for leading streams of said mixture from said chamber tothe engine cylinders.

4. The combination with a multi-cylinder internal combustion engine ofan inlet manifold comprising a toroidal chamber, adapted to receive amixture of fuel and air and to guide the same along an endless path,means for delivering a fuel-air mixture into said chamber in a directionto cause movement of the mixture along said path, and conduits forleading streams of saidmixture from said chamber to the enginecylinders, the inlet ends of said conduits being disposed in the'planeof said chamber and extending outwardly from said chamber in directionssubstantially tangential to the said chamber.

5. The combination with a multi-cylinder internal combustion engine ofan inlet manifold comprising a toroidal chamber adapted to receive amixtureof fuel and air and to guide the same along an endless path,means forintroducing into said chamber, at the innerside thereof, aplurality of streams of fuel and air mixture in directions substantiallytangential to the said chamber, and conduits for leading streams of themixture from the said chamber to the engine cylinders, the inlet ends ofsaid conduits communicating with the interior of the chamber throughapertures formed in the other side of the chamber wall.

6. The combination with a multi-cylinder internal combustion engine ofan inlet manifold comprising a toroidal chamber adapted to receive amixture of fuel and air and to guide the same along an endless path,means for introducing into said chamber, at the inner side thereof, aplurality of streams of fuel and air mixture in directions substantiallytangential to the said chamber, and conduits for leading streams of themixture from the said chamber to the engine cylinders, said conduitshaving the portions thereof adjacent said chamber disposed tangentiallythereto in the plane of the chamber, and. extending outwardly therefrom.

.7. The combination with a multi-cylinder internal combustion engine, ofan inlet manifold comprising a toroidal chamber adapted to receive amixture of fuel and air and to guide the same along an endless path,means for delivering outwardly into said chamber a substantiallytangentially directed stream of such mixture through an aperture formedin the inner wall thereof, apertures in the outer wall of the chamberthrough which streams of such mixture may be tangentially withdrawn, andconduits for leading said streams to groups of engine cylinders,respectively.

8. An inlet manifold for an internal combustion engine comprising aplurality of conduits for leading streams of fuel and air mixture togroups of cylinders, respectively, and means for supplying all of suchconduits simultaneously from a common body of mixture which movescontinuously and unrestrictedly along a closed path within a toroidalchamber.

9. An inlet manifold for multi-cylinder internal combustion enginescomprising, in combination, a toroidal chamber for the circulation of amixture of fuel and air, stationary means having spirally formedpassages for introducing such a mixture into said chamber, the inflowingstreams being similarly directed by said means, and a plurality ofoutlet passages for withdrawing mixture from the chamber, said passagesbeing disposed tangentially to the toroidal chamber so as to permit theready entry of gases thereinto.

10. An inlet manifold for multi-cylinder internal combustion enginescomprising a toroidal chamber, stationary spirally arranged ducts havingtheir outer ends opening into said chamber, said ducts being disposedsubstantially in the plane of the toroidal chamber, a passage forleading mixture simultaneously to all ducts, and a plurality ofdischarge apertures in the outer wall of the toroid.

11. The combination with a multi-cylinder internal combustion engine ofan inlet manifold comprising a chamber shaped to guide a fuelair mixturealong a closed path, stationary means for delivering a fuel-air mixtureinto said chamher in a direction to cause movement of the mixture alongsaid path, said means being designed to insure that the velocity of theinfiowing stream is approximately the same at all points, and conduitsfor leading streams of said mixture from said chamber to the enginecylinders.

12. The combination set forth in claim 11 in which the said meanscomprises a conduit defined by two mutually facing conical surfacescoaxially disposed, said surfaces converging outwardly from the axistoward the chamber.

13. The combination with a multi-cylinder internal combustion engine, ofan inlet manifold comprising an elongated chamber of substantiallyconstant cross-section for guiding a stream of fuel and air mixturealong a closed 10 path, stationary guide means for directing a movingstream of fuel and air mixture into said chamber in a direction to causemovement of the mixture along said closed path,-and separate conduitsfor leading streams of said mixture from said chamber to the enginecylinders.

ELLIOI'I G. REID.

